The examination of the armature of the males of all the hitherto described species of the genus Glossina, with the exception of G. maculata, Newstead,* has not only revealed some very striking morphological characters, but has led to the discovery of three new species† and the re-establishment of Bigot's G. grossa.‡ One of these new species, G. submorsitans, Newstead, has hitherto been overlooked through its striking similarity to G. morsitans. Morphologically these two species are separable chiefly by the small but important organs herein described as the median lobes; these characters will be best understood by reference to the accompanying figures (figs. 15ml, 16ml), in which the difference is as well marked as that between the holoptic and dichoptic heads found in certain groups of Diptera. G. palpalis, R. D., and G. tachinoides, Westw., are also very closely allied in the general form of the armature of the males, but they are easily separable by the minute differential characters of the inferior claspers (figs. 9ic, 11ic).